There is a tremendous need for contrast reduction in applications such as image-processing, medical imaging, realistic rendering, and digital photography. For example, in photography a major aspect of the art and craft concerns the management of contrast via multiple means e.g. exposure, lighting, printing, or local dodging and burning. Poor management of light-under or over-exposed areas, light behind the main character, etc.—is the single most-commonly cited reason for rejecting photographs. This is one reason why camera manufacturers have developed sophisticated exposure-metering systems. Unfortunately, exposure only operates via global contrast management—that is, it recenters the intensity window on the most relevant range. If the range of intensity is too large, the photo will contain underexposed and overexposed areas.
It would, therefore, be desirable to provide a method which reduces the contrast of an image while maintaining the detail of the image such that high-dynamic-range images can be presented.